The present invention relates generally to seaming machines. A seaming machine is used to seam a lid to a contents-filled container body so as to form a sealed container. The seaming machine typically has two seaming rollers associated with the seaming machine to form a sanitary seam, also called a double seam, between the container body and the lid.
Conventional seaming rollers are positioned by mechanical cams controlled by mechanical drives, gear trains and the like, all of which are carefully coordinated and interlinked with a drive that rotates the container body with respect to the seaming rollers. Due to the complex linkages uses in conventional seaming machines and reliance on primarily mechanical drives, it is very time-consuming to make adjustments to a seaming machine when the machine becomes out of tolerance, or if a different size container is used. For example, it may take as long as an entire workday, as well as the swapping of parts, to change a machine if a different container size is used. The changeover results in lost production time and requires skilled, hard to find,, machine operators. A conventional seaming machine, by virtue of its inherent design, is also limited in the range of different container sizes that it can be adjusted to handle.
When packaging goods which spoil due to exposure to air, the air is removed from the container before the lid is sealed thereon. One process for removing the air and which avoids the necessity to seam under a vacuum, is to inject liquid nitrogen into the container before the lid is seamed onto the container. As the liquid nitrogen vaporizes, the resultant nitrogen gas drives out the air. This process requires precise timing to ensure that substantially all of the liquid nitrogen vaporizes and that no air leaks back into the container before the lid is seamed on. It is very difficult to achieve the precise timing.
Accordingly, there is a need for seaming machines and processes which overcome the problems discussed above.